High velocity outflow in the extended emission-line region of the seyfert galaxy NGC 7319

We found a high velocity and large-scale outflow in the extended emission-line region (EELR) of the Seyfert 2 galaxy NGC 7319 with optical long-slit spectroscopy. The EELR elongates similar to 10(n) toward south-southwest direction whose position and direction is coincident with those of the radio emission. The velocity of the outflow comes up to 500 km s(-1), and its extent is 4 kpc. The outflow which we found in NGC 7319 is one of the largest outflowing phenomenon that have ever been found in Seyfert galaxies. Comparing observed line intensity ratios with the photoionization models and the shock ionization models, it is indicated that the outflow gas is predominantly photoionized by the ionizing radiation from the nucleus. The electron density of the nucleus and that of the outflowing gas are estimated from [S II] doublet ratio as 300 and 600 cm(-3), respectively. The electron density of the outflowing gas is very high, and it is a rare case that the electron density of the EELR is higher than that of the nucleus. The volume filling factor of the EELR/outflow of NGC 7319 was found to be very small, 10(-4)-10(-5). This small volume filling factor and relatively high electron density suggest that the outflowing gas would comprise many small filaments or blobs which are compressed by interaction of the outflow with interstellar matter. We have compared the number of ionizing photons which is required to ionize the EELR to that towards the line-of-sight direction. It is shown that the number of ionizing photons which is required to ionize the EELR is larger than that towards the line-of-sight direction by at least one order of magnitude. This indicates a strong anisotropic nuclear ionizing radiation which could be produced by a obscuring torus. (C) 1996 American Astronomical Society.